Rumblings, June 1971

Plugs.—Over the years readers of Motor Sport, knowing the Editor’s liking for old bits and pieces, have generously thrust into his hands ancient sparking plugs, some obviously taken from long-since defunct engines, others brand-new and sometimes in the original, unopened tin boxes or cartons.

These plugs began to form quite a unique collection and a few years ago the Champion Sparking Plug Company Ltd. of Feltham, on being asked if it could find some discarded show-cases in which to house them, very generously took over the whole thing, cleaning, documenting and mounting these plugs in two magnificent showcases, neon-lit.

The collection, which is illustrated in colour in the Pictorial section, is pretty comprehensive. The exhibits it contains range from plugs of around the year 1900, to modern 14 mm. Champions of the well-known J (3/8 in.-reach), H (7/16 in.-reach), L (1/2 in.-reach) and N (3/4 in.-reach) type. There are even three tiny plugs for model i.c. engines, a 10 mm. Champion racing plug as used in today’s F.1 cars, a Champion Jet Igniter for Rolls-Royce Dart engines in turboprop airliners and, the final exhibit, a Champion Jet Igniter for the Rolls-Royce Olympus 593 engines of the Concorde.

These latter were contributed by Champion themselves, but the older plugs presented by readers of this paper form a significant collection. For instance, in the first showcase, which covers roughly the period 1900 to 1930, there are such items as French Oleos, Apollo, Castle and Triumph plugs varying from 1/4 in. to 7/16 in.-reach, an unidentified early competition plug, and various Champion plugs for the Model-T Ford with the 1/2 in. gas taper thread. These are backed up by such forgotten makes as Rajah, Vallier 3-3, Warrior and Sparko (USA). Unusual plugs include a Champion with inbuilt petrol-primer, and a very long Lodge for use in sleeve-valve engines. All these date from circa 1910.

Then come a series of First World War aviation plugs, followed by plugs of the 1920s. The latter embrace Lissen BS2, JD (USA), Defiance, a French Eyquem, Macoilaire, Magneto AV, Goodyear and an Oda Palantine 69 aeroplane plug amongst rare specimens, as well as two different-type Lodge double-pole plugs for dual-ignition systems, a Bosch R220, Bluemel, Bluemel Mascot, Apollo, KLG F52 and Lissen S5.

This case of early plugs, mostly 18 mm. or 1/2 in. gas thread types, includes Sphinx, Plantomac 8, a Lodge BR8 competition plug, commercial Champion 3X and 2Com.L, with 7/8 in. x 18 threads, industrial-engine Champion 37 and 38, of about 1920, with 1 in.-gas taper threads, and AC, Forward commercial, KLG G1 heavy-duty, Beru, SEV, and AC Sphinx B11 of the 1930s. Especially interesting are some special aviation plugs of about 1925—a Lodge H51 with copper central electrode and disc earthing, a KLG Rotary RF with special-purpose disc electrodes and a KLG F12.

Racing plugs are represented by Champion R1, Lodge BR2, BR4, BR7, BR8, BR29 and BR40, a Lissen R202, all these being 18 mm. vintage types, and there is even a tall slim 12 mm. 1/4-in. reach KLG521 with copper electrode, believed to have been used in the “flat-iron” Thomas Special.

The display in the second case, from a later era, is equally comprehensive. Here we see 14 mm. KLG racing plugs, like the 646, the aviation KLG C8, a Lodge Aero, the popular 14 mm. Lodge CV and CVL commercial plugs, the latter with mica insulator, the Lodge HVL with Sintox insulator, and such types as KLG G2, Champion C4XS, AC KD7, KLG KS5 motorcycle plug, Champion 5 Com. and Y, the latter made in 1934 for Ford engines, the sports Lodge H13, the universal Champion 7A, a heavy-duty KLG 291 of 1935, a Champion 44 for later industrial engines, and examples of last-war and later Champion N7, Y6, 901, C5 and A25, respectively for tractors, American cars, industrial engines, Fordsons and Model-Ts. Different again are such specialised plugs as the Lodge SP14 radio-shrouded plug of 1938 and a Lodge HNP with platinum-tipped electrode.

Plugs of the 1960s embrace Marchel and Eyquem from France, NGK from Japan, Bosch and Beru from Germany, and Champion, KLG, AC, Lodge and Autolite from the UK.

A fascinating array! From it the development of the sparking plug emerges. Single piece plugs, impossible to clean, had almost gone by the 1920s, although Bosch still made them. When sand-blasting was introduced in the 1930s non-detachable plugs returned to favour and are now universal. Early insulators were mainly of ceramic, wrongly called porcelain, but mica insulators were later quite popular, particularly KLG’s famous disc-upon-disc insulators. However, problems of manufacture and damp penetration had to be contended with, and when the supply of mica from Madegascar dried up with the Second World War, there was a universal return to ceramic insulation, but not before Lodge had tried mica insulators sheathed in ceramic.

Early ideas for electrodes included those with two, even three points, the idea being to spread wear caused by burning. This merely resulted in loss of the correct gaps at each point, as bending the central contact to try to restore one of them invariably damaged the plug. The modern bent-over single-electrode enables the gap to he maintained by bending the wire.

It is interesting that the sparking plug, that innocent non-mechanical component which is essential to all modern i.c. engines except diesels and which has to withstand temperatures fluctuating between —40° C and 1,000° C while containing electrical pressures of up to 30 kV, has not changed greatly since Lenoir invented it in 1860. Electrodes changed from platinum through plain steel, nickel steel and (in the 1930s) copper, to nickel alloy welded to steel wire, with indium and gold/palladium alloys, or copper-filled tubes (as in modern NGK plugs) for special industrial and aviation applications. The attempt to combat excessively oily engines by extended electrodes, much prone to burning, is seen in the earlier plugs. Plug bodies were fixed to the cylinder by flange fittings in a few pre-1900 designs, cast-iron bodies being used, but screw-in plugs soon became universal, their shells made of gunmetal, cast-iron, brass (up to 1915) and steel.

All this is seen in the display in question, for which W.B. is indebted to those who supplied the exhibits and to Champion for so effectively setting them out. He hopes he will still be offered rare sparking plugs, so that they may, perhaps, be incorporated in an even more comprehensive display.

The Senior Service Hillrally.—During the first weekend in May, fortunately in magnificent weather, we found ourselves on mini-mountains at places like Nat-y-Fyda and Carneddau, watching a prototype Hillrally for 4 x 4 vehicles sponsored by the Senior Service cigarette people.

There is nothing new about competitive events for four-wheel-drive vehicles, which clubs like the Rover Owners’ Association, the All-Wheel-Drive Club and regional Rover Owners’ Clubs have run for some years. The difference about this Senior Service event was that instead of using trials sections which drivers had to attempt to clear, competitors were timed over long, difficult stages and had time schedules on ordinary roads to observe, as in a modern rally. So the entries had to be, in effect, cross-country vehicles capable of a practical road performance. There were seven classes, sub-divisions being mainly on engine size, but with a separate Haflinger class, another for 4 x 4 specials, and one for diesel-engined vehicles, the last-named attracting a lone Land-Rover.

A reasonable entry of 45 was received, comprising four Haflingers, three entered by Steyr-Daimler-Puch GB Ltd., four Range Rovers, one of which was a works entry, 26 Land-Rovers of different ages, engine capacities and type, apart from the aforementioned oil-burner, these including three entered by the British Army Motoring Association, half-a-dozen Jeeps, a Toyota, which on engine size competed with the Range Rovers, and three specials consisting of a Couzens-Renault, which wasn’t completed in time, a V8-engined Land-Rover and a B40 Land-Rover. In fact, only two non-starters were posted, and contrary to pessimistic predictions, 34 entries completed the tough course, which embraced mud-sections, long uphill grinds enlivened by yump-promoting rock outcrops and fording the River Wye.

Publicity was handled by Good Relations Ltd., who did an excellent job, even to a refreshment tent near the summit of Carneddau. A smoothly-flown Bell Jet-Ranger helicopter belonging to the David Brown Organisation was at the disposal of the BBC TV team; it landed adjacent to the stages and deposited them close to their hotel in Llandrindod Wells.

The Hillrally is a new sport in Britain, but it was based on the Rallye des Cimes, a similar event based on the Pyrenees for the past 15 years. Senior Service, indeed, are contemplating an International Hillrally, perhaps in October. The Secretary of the Meeting was Roger Fell, Michelin put out the route markers, and Burmah-Castrol sent a service vehicle.

The advent of this type of contest in this country has introduced some fresh safety requirements. Dean Delamont was taking stock, the vehicles were required to have full safety harness and proper roll-over bars, and the Scrutineer was troubled by mud-coated chassis which precluded safety inspection, inadvertently detachable wheels on old Land-Rovers, doors which flew open or didn’t exist and petrol tanks beneath jeep seats, etc. It will be a pity if those who these days exist to protect sportsmen from their sport frame regulations which might materially uplift the cost of competing.

One gathers, too, that The Times criticised the Hillrally on the grounds of desecration of the countryside, but in view of the vast expanse of wild Welsh terrain given over to firing ranges, sheep grazing, bird watching, but little else, and the wild weather which quickly obliterates fresh scars, this hardly seems valid unless such events increase greatly in frequency. In any case, this initial experiment took place largely on private or Forestry land and, as the sponsors pointed out, “it should gain favour in a world where restrictions are daily making other forms of motoring sport more difficult, in that it takes place in fairly remote country and then only with those vehicles which belong to the country…”.

For our part, we enjoyed what we saw. There were Range Rovers and Land-Rovers seemingly bogged down for evermore, yet they winched themselves out. The Midland Rover OC’s recovery vehicle went in up to its front hubs, but that got clear. It was excellent PR for 4WD, but it would have been nice to have seen Ford-Ferguson, Gypsy, Champ and Unimog opposition to the afore-described entry. As it was, the Jeeps seemed more effective than many of the Land-Rovers and the Haflingers outstanding.

The Overall Winner was R. Craythorne, driving the Rover Company’s Range Rover representing the ROA. Second place went to M. Green in a much older Land-Rover, for the Peak & Dukeries Club, third place to K. Kennington’s Land-Rover, for the same Club. The Class Winners were Craythorne (Range Rover), L/Cpl. E. Price (Land-Rover), for the British Army MA, M. Green, and A. Souter (Haflinger), for the All-Wheel-Drive Club, Senior Service (Gallaher Ltd.) proved generous and capable sponsors of this novel event, with technical help from Good Relations Ltd. and the Peak & Dukeries Land-Rover Club.